A sample of glass is glazed in an acoustic test house where it is subjected to various frequencies. Sensitive microphones compare the source side with the receiving side to produce a plot and measurement of the effect of the glass at each frequency. The chamber is calibrated to ensure that it is the glass performance only that is being measured. We use the data to present the performance by frequency band and by the shortforms such as Rw and Rtra. The figures show the attenuation.